برخي از خصوصيات زيستي ماهي شلج (Leuciscus vorax (Heckel, 1843 در تالاب شادگان

Some biological characteristics of Leuciscus vorax (Heckel, 1843) in Shadegan wetland

در اين تحقيق برخي از خصوصيات زيستي ماهي شلج (L. vorax) در شادگان مورد بررسي قرار گرفت. نمونه برداري ماهانه در پنج ايستگاه از تالاب شادگان شامل دورق (ماهشهر)، رگبه، خروسي، سلمانه، عطيش انجام گرديد. تعداد 456 نمونه ماهي با استفاده از تور گوشگير ثابت صيادي (چشمه 45 ميلي متري) در فروردين 1392 تا اسفند 1392 صيد گرديد. ميانگين طولي جنس ماده و نر ماهي شلج برحسب ميلي متر به ترتيب 31±262، 29±265 و ميانگين وزني برحسب گرم به ترتيب 34±192، 41±194 به دست آمد. رابطه طول-وزن اين گونه (w=0.00002L2.88 (R2=0.88 به دست آمده و آلومتريك منفي بود. زمان تخم ريزي براي ماهي شلج در تالاب شادگان دي و بهمن ماه است. طول بلوغ 266 ميلي متر، وزن بلوغ 162 گرم و ميزان توليد به ازاي بيوماس آن ها 0/44 به ازاي سال به دست آمد. شاخص هاي رشد ماهي شلج به ترتيب طول بي نهايت 498 ميلي متر، ضريب رشد 0/45 به ازاي سال و طول صفر 0/16- محاسبه شد. با توجه به خصوصيات زيستي ماهي شلج و بر اساس شاخص انجمن شيلاتي امريكا (AFS) اين ماهي جزء ماهيان با آسيب پذيري ذاتي متوسط به حساب مي آيد.

In this study, some biological characteristics of L. vorax were investigated in Shadegan wetland. Monthly sampling was done at five stations of Shadegan, including Doragh (mahshar), Rogabe, Khorosy, Salmane, and Atish. For this purpose, 456 specimens were caught using gill nets with 45 mm mesh from April 2012 to March 2013. Average and standard deviation length of female and male L. vorax were calculated per millimeters as 262 ± 31, 265 ± 29 and the average and standard weight in grams were measured, 192 ± 34, 194 ± 41, respectively. Length-Weight Relationship was calculated as negative alometric which was Y=0.00002L2.88 (R2=0.88). Furthermore, spawning period was determined in January to February. In addition, maturity length and maturity weight were calculated as 266 millimeters and 162 grams, respectively, and production rate per biomass annually was computed as P/B= 0.44. Fish growth indices were calculated to be L∞=498(mm), growth rate K=0.45 (yr-1) annually and to=-0.16 respectively. According to biological characteristics and with regard to American Fisheries Society (AFS) indices, this species is classified as mediate vulnerable group fishes.